Tikal National Park , the oldest and best known of Guatemala’s national parks, was created in 1956 and declared a UNESCO World Heritage Site in 1979. It encompasses 222 square miles of primary tropical forest and protects a vast array of wildlife, as well as harboring the remains of one of the Mayan civilization’s greatest cities. Tikal is understandably high on the list of priorities for any visitor to Guatemala and shouldn’t be missed.
Laguna del Tigre National Park  is a vast park on the northwestern corner of Petén encompassing important wetlands, the largest in Central America. It also contains the only remaining populations of scarlet macaws in Guatemala, which are being protected via ongoing conservation efforts at a biological research station.
Oil drilling, present before the park’s creation, continues inside the reserve, despite protests from environmental groups and its having been declared a violation of the park’s intended use. Also going on inside the park are the clandestine activities of loggers, wildlife poachers, drug traffickers, and smugglers of illegal immigrants across the border to Mexico. The western border with Mexico running along the park’s boundaries has also become permeable to incursions from Mexican peasants, who have made a once razor-sharp border between the two countries look more like patchwork.
Archaeologists working in these parts enter under the escort of heavily armed guards. Visitors to this park should limit their activities to those centered around the Scarlet Macaw Biological Research Station, as the current lawless conditions prevent my recommending more in-depth explorations of this wild frontier.
Sierra del Lacandón National Park  is a densely forested, rugged mountain park said to harbor one of the largest populations of jaguars in all of Central America as well as an incredible degree of biodiversity. Hidden in the forests are the remains of several Mayan sites, the most important of which is Piedras Negras, deep inside the park along the Usumacinta River, which marks the western border with Mexico. The park is privately administered by Fundación Defensores de la Naturaleza. In June 2006, together with The Nature Conservancy, it completed the purchase of 31,000 hectares (77,000 acres) of privately owned land in the core zone of Sierra del Lacandón. There are a number of ranger stations inside the park, the most prominent of which is at Piedras Negras.
A large park in the northern section of the Maya Biosphere Reserve near the Mexican border, Mirador–Río Azul National Park  protects vast expanses of tropical forests and the remains of several Mayan cities. Among the most impressive ruins are those at El Mirador , including El Tigre temple, which is 18 stories high with a base the size of three football fields. Other sites inside the park include Río Azul  and Nakbé, visible from the top of El Mirador’s massive temples. Access to the park is by foot, a full day’s walk from the village of Carmelita, or helicopter.
Laguna Lachuá National Park  consists of a circular lagoon in the Ixcán jungle west of Cobán surrounded by 14,500 hectares of tropical forest and several miles of hiking trails. The karst limestone nature of this placid pool makes it a very attractive turquoise. A high concentration of mahogany trees in the surrounding forests has made it vulnerable to clandestine logging.
One of Guatemala’s oldest protected areas encompassing the watershed of its namesake river connecting Lake Izabal with the Caribbean Sea, Río Dulce National Park  covers 7,200 hectares along its 30-kilometer-long course. In many places, the banks of the river are shrouded in dense tropical forest punctuated at one point by a large canyon with high rock faces.